Backdoor
Active Member
Hello All -
I am having the dreaded cold start sputter and smoke until the engine warms up and then it runs great until the engine goes cold again. Typically it only sputters a little until it warms up but we took a trip out to Spokane about a week ago and in Zero Fahrenheit temps it was pretty rough starting up. After attempting to start 2 or 3 times it would sputter pretty badly and spit and cough for quite a few minutes before I could get it to rev up to 1200 -1500 rpm and then it would warm up and run great.
From the description below and the other work that I have done to the vehicle I have to assume that the only thing left is that the IP pump needs a new seal. Another indicator for this is that I do have some shifting issues until the vehicle gets warmed up in that it wont shift into third gear until a very high rpm (4000 or so). Once warmed up it runs fine and shifts with no issue.
Air vs oil seepage through the main shaft IP seal. If the seal has degraded ‘slightly’ then air will seep through causing white smoke on startup and after a few mins due to heat introduction, it expands with the problem disappearing.
If the seal has degraded more than ‘slightly’ then oil will be introduced as well leading the other issues. See below a customer from 2010 /
Symptoms:
Engine starts easy on cold starts but will idle roughly (almost dying) after start up with lots of blue smoke coming out of the exhaust. It will idle and run smoother after a couple of minutes but will always shift irregularly on the drive to work. It had very bad fuel consumption (approximately 430 kms on about 65 liters) but I drive 900 ft up everyday. There were signs of black smoke when accelerating to speed up. The very annoying issue aside from the fuel consumption was its shifting pattern. The transmission doesn't know or can't really figure out which gear to shift at different rpms.
Diagnostics:
Engine and transmission computer are not on the same frequency...meaning the engine is not delivering the correct power based on the throttle position sensor and kickdown cable adjustments. We suspect a bit of fuel dillution (explains the blue smoke) and very rich condition (black smoke on acceleration) that the engine generally runs on.
Solution:
Well, the injectors were all cleaned up, its pressure settings corrected and spray patterns were met. We adjusted the throttle position settings and kick down cable adjustment as well. Having done that, we tested the L400 again and overall conditions improved but not satisfactory from what it should be. Only one thing remains that will contribute these symptoms as well....the injection pump. We removed it and did the overhaul and reseal. These were our findings on the injection pump....thru time, the front shaft oil seal hardens up and allows a certain amount of oil to get inside the pump. The mechanical fuel pump is inside the IP and sucks in the oil thru this seal as the whole front of the IP is exposed to oil along the timing chain/gear drives. This explains the blue smoke in the mornings as the oil slowly gets in overnight. As the oil affects the internal parts of the pump as well, the 'usual' governor sleeve gets sticky and thus affects its functions and will not respond to the fuel requirements it needs to deliver at different load conditions. So, after the IP overhaul, my L400 drives and shifts perfect! Fuel consumption improved to about 550kms on 65 liters. No smoke. Starts easy and smoothly even on cold days.
So I figured I would start this thread and let you guys know about all the challenges I will be facing in taking out the IP Pump and getting it rebuilt/serviced and then put back into the van.
I am having the dreaded cold start sputter and smoke until the engine warms up and then it runs great until the engine goes cold again. Typically it only sputters a little until it warms up but we took a trip out to Spokane about a week ago and in Zero Fahrenheit temps it was pretty rough starting up. After attempting to start 2 or 3 times it would sputter pretty badly and spit and cough for quite a few minutes before I could get it to rev up to 1200 -1500 rpm and then it would warm up and run great.
From the description below and the other work that I have done to the vehicle I have to assume that the only thing left is that the IP pump needs a new seal. Another indicator for this is that I do have some shifting issues until the vehicle gets warmed up in that it wont shift into third gear until a very high rpm (4000 or so). Once warmed up it runs fine and shifts with no issue.
Air vs oil seepage through the main shaft IP seal. If the seal has degraded ‘slightly’ then air will seep through causing white smoke on startup and after a few mins due to heat introduction, it expands with the problem disappearing.
If the seal has degraded more than ‘slightly’ then oil will be introduced as well leading the other issues. See below a customer from 2010 /
Symptoms:
Engine starts easy on cold starts but will idle roughly (almost dying) after start up with lots of blue smoke coming out of the exhaust. It will idle and run smoother after a couple of minutes but will always shift irregularly on the drive to work. It had very bad fuel consumption (approximately 430 kms on about 65 liters) but I drive 900 ft up everyday. There were signs of black smoke when accelerating to speed up. The very annoying issue aside from the fuel consumption was its shifting pattern. The transmission doesn't know or can't really figure out which gear to shift at different rpms.
Diagnostics:
Engine and transmission computer are not on the same frequency...meaning the engine is not delivering the correct power based on the throttle position sensor and kickdown cable adjustments. We suspect a bit of fuel dillution (explains the blue smoke) and very rich condition (black smoke on acceleration) that the engine generally runs on.
Solution:
Well, the injectors were all cleaned up, its pressure settings corrected and spray patterns were met. We adjusted the throttle position settings and kick down cable adjustment as well. Having done that, we tested the L400 again and overall conditions improved but not satisfactory from what it should be. Only one thing remains that will contribute these symptoms as well....the injection pump. We removed it and did the overhaul and reseal. These were our findings on the injection pump....thru time, the front shaft oil seal hardens up and allows a certain amount of oil to get inside the pump. The mechanical fuel pump is inside the IP and sucks in the oil thru this seal as the whole front of the IP is exposed to oil along the timing chain/gear drives. This explains the blue smoke in the mornings as the oil slowly gets in overnight. As the oil affects the internal parts of the pump as well, the 'usual' governor sleeve gets sticky and thus affects its functions and will not respond to the fuel requirements it needs to deliver at different load conditions. So, after the IP overhaul, my L400 drives and shifts perfect! Fuel consumption improved to about 550kms on 65 liters. No smoke. Starts easy and smoothly even on cold days.
So I figured I would start this thread and let you guys know about all the challenges I will be facing in taking out the IP Pump and getting it rebuilt/serviced and then put back into the van.
